Clinical Evaluation of All Ceramic FPDs Using Y-TZP Framework

Objectives: Recently, new metal free materials for crown and fixed partial dentures (FPDs) such as yttria stabilized tetragonal zirconia polycrystals (Y-TZP) have been introduced to the dental profession. Clinical applications of Y-TZP frameworks have expanded the range of indications of all ceramic fixed partial dentures in the posterior region. Y-TZP exhibits excellent mechanical properties. The bending strength of Y-TZP is over 1,000 MPa and is much greater than that of Procera and Vita Inceram zirconia. These systems enable the fabrication of the long span fixed partial dentures of more than 3 units in the posterior region. The aim of this study was to evaluate the clinical performance of all ceramic FPDs using Y-TZP framework.

Material and methods: We began a longitudinal study to evaluate the clinical performance of all ceramic FPDs using Y-TZP framework in December 2002. Over 80 Cercon Smart Ceramics FPDs (DeguDent) were fabricated and clinically evaluated. We checked periodontal condition of the abutment teeth (plaque index, gingival index and pocket depth), abrasion and tooth mobility of the antagonists, change of the occlusal contacts, chipping of the veneering porcelain and fracture of the framework. We also measured marginal fitness of FPDs using silicone impression material. The longest period of observation was 5 years.

Result: The mean marginal discrepancies of the FPDs were 70.9 µm. No cases of fracture of the framework have been observed. Chipping of the veneering porcelain was observed in only three cases. There were no significant changes in the measurement value of tooth mobility of the antagonist, plaque index, gingival index or pocket depths. To date, all ceramic fixed partial dentures using Y-TZP framework have shown good clinical results.

Conclusion: The clinical application of Y-TZP framework expanded the range of indications of metal free restorations.